In a mixing bowl, stir together the sour cream and salsa and set aside.

Spread 3 cups of the rice in the bottom of the dish and top with half of the sour cream mixture. Scatter 1 1/2 cups of the cheese over the casserole and top with the beans, the remaining rice, and the remaining sour cream mixture. Bake for about 15 minutes.

Meanwhile, toss the crushed tortilla chips with the remaining 1 1/2 cups of cheese. Remove the casserole from the oven and sprinkle the chips mixture over the top. Bake for about 5 minutes longer, or until the cheese melts and the casserole is bubbling and heated through. Serve hot.